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(No Model.)

F. B. NICHOLS.

APPARATUS FOR BVAPORATING SIRUPS AND VISGOUS SUB$ TANGES No. 276,192. Patented Apr.Z4,1883.

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50229168865.- Invenior:

N. PETERS. Pmwumn n rm, Wnhingion. v.0

NITED' STATES FREDEBIO B. NICHOLS, OF HALIFAX, NOVA SOOTIA, CANADA, ASSIGNOR OF ONE-HALF TO OATHOART THOMSON, OF SAME PLACE.

APPARATUS FOR EVAPORATING SIRUPS AND VISCOUS SUBSTANCES.

SPECIFICATION forming part of Letters Patent No. 276,192, dated April 24, 1883. v

Application filed August 11, 1882. (No model.)

' To all whom it may concern:

Be it known that I, FREDERIO BOOTH N1011- oLs, a citizen of the United States, residing at Halifax, in the county of Halifax and Province of Nova Scotia, Dominion of Canada, have invented a new and useful Apparatus for Evaporating Sirups and Viscous Substances, of which the following is a specification.

My invention relates to improvements in evaporating apparatus in which sirups or other semi-liquids too thickor viscous to flow freely are carried up by a slow movement of an endless band or apron for the purpose of exposing a large surface to the action of hot or dry air, and removing it from the endless band when sufficiently concentrated. I attain these objects by the appliances illustrated in the accompanying drawings, in which- Figure 1 is a front elevation, rope, pulley, and weight being omitted. Fig. 2 is a vertical end view, partly in section. Fig. 3 is a top view of pressure-rollers and scrapers with guide-bar and receiving-trough.

This invention is intended as an improvement on the apparatus for evaporating or concentratin g liquids, &c., specified and claimed by me in United States Patent No. 265,974, dated October 17,1882. In operating with the apparatus previously patented all thin liquids that can be brought to a sirupy or viscous condition can be concentrated to that extent,

but beyond that state it becomes inoperative,

and in all operations for further concentration great difficulty is encountered except by vacuum-pan. In order to overcome the difficulties presented, I adopt the following device:

A broad endless band or apron, of cloth or other suitable material, a, is stretched over rollers 12 c, that are kept in position by framework 70 is, placing 1) vertical to 0. These rollers b 0 should be cylindrical, and have flanges g at each end to keep the band or apron from running off to the side or end. Two other rollers, f h, smaller in diameter than I) c, are placed in the position shown in Fig.2. f is held in position by the frame k 70, Fig.1. One of the journals on which it turns extends out beyond the frame for attaching the pulley Z or other means of applying a continuous rotary motion to the roller. Roller h is held or suspended by the levers or frames at n, placed at each end and pivoted, at 0, to the frames k k. A cross-bar, r, connects and holds them to gether, and a rope or cord is attached to the center of the bar, one end of which passes up over the pulley s for the purpose of raising it to the position u, shown by the dotted lines. The other end of the rope hangs down, and has a weight, 1;, attached for the purpose of exerting pressure on the band, the amount of pressure being regulated by the amount of weight attached.

A scraper, t, of the form shown in the drawings, nearly encircles roller f, fitting closely. Fastened at each end to the frames is k is a guide bar or rod, 00, on which it slides and keeps it from coming in too close contact with the endless band, and allows it to be pushed or pulled from end to end alternately by means of a small rod, wire, or cord attached to the scraper at t". A scraper, y, the counterpart of t, is fitted to roller h. A guide-bar, w, is fastened at each end to n a, on which it slides by the same means as scraper t.

Rollers f and it should be of metal, and about two inches longer than the width of the endless band, to allow the scrapers to remain at rest at either end oi the pressure-rollers withouttouchingtheband. Receiving-troughs c u should be provided at each end to catch the material collected by the scrapers.

A roller, d, which may be covered with cloth to make it absorbent, if desirable, runs on its journals in a trough, m, that contains the sirup or other substance that is to be evaporated. This roller dis kept in contact with the band a as it passes over roller 0, and rotates with it.

All the rollers should run truly and freely on their journals in their respective bearings, which should be so placed as to keep the rollers parallel with each other both vertically and horizontally.

The whole apparatus should be placed in a chamber supplied with hot air, or for some purposes preferably with air dried by means of a dessicating agent.

The mode of operation is as follows: The endless band being in tension and in contact with the driving-roller f, by pressure of roller h with it weight 10, f is rotated in the direction of the arrow, causing all the other parts to move in the direction of the arrows annexed. This causes the roller d to bring up the material contained in trough m and spread it over the endless band as it ascends, and is carried up over roller 1) and down between the driving and pressure rollers f h. The pressure should be sufficient to squeeze off all the evaporated material not contained in the fiber of the band. This will gradually collect on the upper side of the rollers, from which it should be removed, when sufficient has collected, by a moderately-quick movement of the scraper from end to end, which will drive it ahead and drop most of it in the receiving-trough. The scraper should remain at the end to which it is moved till it is necessary to move it to the other end for the same purpose. The time of rotation should be so regulated in relation to the drying power of the air that the proper degree of concentration is obtained by the time it reaches the pressure-rollers, which will remove it so long as there is the least plasticity retained by it. Most of it is collected by roller h, but some will pass through the fiber of the band and be collected by roller f.

For large operations very long bands, presenting a large superficial area, should be'employed, and a number of them geared together can be placed in one heating or drying chamber; By thus presenting a large surface from which evaporation takes place a moderate heat, never exceeding and seldom equaling 150 Fahrenheit, produces very rapid eoncen tration without scorching or other injurious effects.

In driving an endless band or apron between two pressure-rollers it is impossible to so regulate the pressure as to pull uniformly on the band, and the disposition is to run to one side and topullone side faster than the other. This, culminating, in timebecomes very troublesome,

and may even rupture the band if not corrected. To obviate this difliculty the roller h is raised to the position shown by the dotted lines at. This can be effected by pulling on the rope passing over pulley s, or by other convenient means, the bearings of roller 1) sliding in slots in the frames k k, and, being pressed up by the springs to w, raise up roller 1) and straighten out the band, as shown by the dotted line 6, when roller h is raised, and on allowing it to drop back it meets the band in its normal position. This should only be done when required and immediately after scraping oft the material collected.

It is obvious that both of these operations of scraping and releasing the band could be performed automatically, but the time for doinglt varies so much thatit would be extremely difiicult, and the whole apparatus requiring constant supervision, it is best accomplished manually.

I am aware that endless bands have been used for conveying many substances, and that pressure-rollers are used for squeezing and thereby removing substances from bands, and make no claim to such uses; but

What I do claim as my invention, and desire to secure by Letters Patent, is-

1. A scraper fitted to each pressure or squeezing roller on the line of their circumference and moving alternately from end to end of said rollers, in combination with guides for keeping the scrapers in proper position with the endless band, in the manner and for the purpose specified.

2. The movable pressure-roller, in combination with springs to w and endless band a, for the purpose herein specified.

FREDERIO BOOTH NICHOLS.

Witnesses:

FREDERICK SUMMERS, DAVID BOUTILIER. 

